iPhone 4 Tripod Mount

Over the weekend I stumbled upon this awesome Instructable by jtsubota "iPhone 4 Tripod Mount".
http://www.instructables.com/id/iPhone-4-Tripod-Mount-1/

The parts list was short and I decided to try to pick up all the required parts after work Monday night. Unfortunately for me, my local hardware store was missing a handful of the (already short) parts list. I almost gave up and was prepared to head home empty handed when I realized I could easily modify the project using my Makerbot and make this work with what I was able to find.

Here is the parts list:
1/4 inch hex nuts
30mm suction cups

Rather than secure all the parts in place using screws like jtsubota did I modeled everything to press fit in place. The nut fits in very snuggly and the suction cups snap into place with a firm push. Once everything is attached it feels really solid. So much so that I can shake my phone by the tripod mount without fear of it disconnecting.

If my calculations are correct, I believe th